Columnar data storage on tape partition

Abstract

A method for writing data from a table to a tape includes setting a number of partitions on the tape, where the number of partitions is greater than or equal to a number of columns of the table to be written to the tape, and writing data from each column of the table to at least one partition of the tape, the at least one partition including two or more wraps, the data is written from a top of the two or more wraps towards a bottom of the two or more wraps in a direction of a width of the at least one partition. The written data is reciprocated from a beginning of the tape to an end of the tape in a longitudinal direction of the tape such that writing of a last data entry of one column ends at a beginning of the two or more wraps.

The invention claimed is: 
     
       1. A computer system for setting partitions on a tape, the computer system comprising:
 one or more processors, one or more computer-readable memories, one or more computer-readable tangible storage devices, and program instructions stored on at least one of the one or more storage devices for execution by at least one of the one or more processors via at least one of the one or more memories, wherein the computer system is capable of performing a method comprising: 
 obtaining a data size S1 of a column to be written to the tape; and 
 dividing the data size S1 of the column by a data size S2 of a wrap of the tape to obtain a quotient N, wherein a result of the quotient N is rounded down using a ROUNDDOWN function. 
 
     
     
       2. The computer system of  claim 1 , wherein data from the column is written to a (N+1) wrap of a partition of the tape when the quotient N is an odd number. 
     
     
       3. The computer system of  claim 1 , wherein data from the column is written to a (N+2) wrap of a partition of the tape when the quotient N is an even number. 
     
     
       4. The computer system of  claim 3 , wherein writing data from the column to a (N+1) wrap of the partition of the tape when the quotient N is an odd number further comprises:
 setting a first area extending from a beginning of a N th  wrap to a data size (S1−(N−1)*S2)/2 as a data writing area in the partition; and 
 setting a second area from a position of a (N+1) th  wrap directly below a last position of the data size (S1−(N−1)*S2)/2 to be written in the N th  wrap to a beginning of the (N+1) th  wrap as data writing area in the partition comprising the data size (S1−(N−1)*S2)/2. 
 
     
     
       5. The computer system of  claim 4 , wherein writing data from the column to a (N+2) wrap of the partition of the tape when the quotient N is an even number further comprises:
 setting a third area from the beginning of the (N+1) th  wrap to a data size (S1−N*S2)/2 as writing data area in the partition; and 
 setting a fourth area from a position of a (N+2) th  wrap directly below a last position of the data size (S1−N*S2)/2 to be written in the (N+1) th  wrap to a beginning of the (N+2) th  wrap as a data writing area comprising the data size (S1−N*S2)/2.